Quick-service restaurants are often the first category people think of when it comes to franchising, and for good reason: They dominate the list of fastest-growing franchises, with 25 out of 106 entries. Particularly popular this year is the frozen-yogurt sector, with four companies ranking, and sandwiches, with six--including this year's No. 1 company, Subway.

But fast food is far from the only sector experiencing rapid growth. Ten senior-care companies made the ranking, including one of the youngest franchises on the list, FirstLight HomeCare (No. 46), which jumped into this already-crowded category in 2010 and has proved itself quickly. Commercial cleaning companies continue to thrive as well, thanks in large part to low startup costs. Eight janitorial franchises ranked, including three in the top 10: Jan-Pro Franchising, Vanguard Cleaning Systems and Anago Cleaning Systems.

The companies on this list are ranked based on growth in the number of open and operating U.S. and Canadian units from July 31, 2011, to July 31, 2012. (Ties are listed alphabetically.) In that time, these 106 companies racked up an impressive 9,945 new North American franchise units.

Keep in mind that rate of growth, while a positive sign, is far from the whole picture when it comes to determining whether a franchise opportunity is right for you. Always do your research--read the company's legal documents, consult with an attorney and an accountant and talk to franchisees--before investing in any business.